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SAN JUAN NATURE NOTEBOOK BY SUSAN VERNON |
Previous columnscurrent columnThe serviceberry and the waxwings | |
Harbingers of spring
posted 02/17/04
For several years, I have followed the hummingbird migration via the Cascadia Hummingbird Report. I discovered the data on an Internet site called Tweeters Birding Email Digests. Every week, beginning in February and running into May, Rufous sightings are posted as the birds follow the first wildflowers up the coast of California, into Oregon, then Washington, and finally through British Columbia to southeast Alaska. What a contrast between counting Trumpeter Swans, North America's largest waterfowl that fly 2,000 miles from Alaska to the San Juans, and monitoring the journey of one of our smallest birds that travels nearly the same distance to the San Juans, but from southern climes. The migration of the Rufous Hummingbirds is keyed, in part, to early blooming plants along the Pacific coast including red-flowering currant (Ribes sanguineum), salmonberry (Rubus spectabilis), Indian-plum (Oemleria cerasiformis), black twinberry (Lonicera involucrata), hairy manzanita (Arctostaphylos columbiana), and the catkins of Hooker's willow (Salix hookeriana). There are other wild plants and ornamentals along the way - and bird feeders, too - but the Northwest natives are the main attraction. The plants are also an important nectar source for bees, early butterflies, and other insects. Here in the San Juans, three plants important to early hummingbirds are the red-flowering currant, Indian-plum, and salmonberry. Once having found the currant, I was determined to catch the others in first bud. From past experience, I knew where to look for the early bloomers. By February 4, I had found all three species in flower - just barely - and my search has continued, encouraged by a string of warm days. I drove to Eagle Cove for the Indian-plum, a relatively uncommon plant in the islands. It is fond of moisture and grows in mixed woodlands and marshy areas. I checked an old acquaintance, anchored on the hillside along the little creek that flows to the sea. It was well on its way into flower. Dozens of buds appeared along its sprawling branches. Several tiny greenish-white flowers were unfolding, and drooped in tight clusters from shocks of lance-shaped, upright leaves.
Near Limekiln, the Oemleria was thriving in proximity to a stand of red alders whose catkins were just about to make their spring growth spurt. I had to look closely to find the first delicate flower, but within another week the shrub will be draped in a cloak of creamy inflorescence. There is at least one more patch of Indian-plum, also called Osoberry, in San Juan Valley; and Atkinson and Sharpe's Wild Plants of the San Juan Islands report that it also grows on Cady Mountain. Our third early enticement is salmonberry. I searched dozens of sites and found only half a dozen flowers. That was enough to get my count started. Salmonberry is a common shrub in the San Juans. It grows in dense thickets where moisture collects, as along the edge of a marsh or stream. Its rich magenta blooms are jewels to behold along handsome buff-colored stalks, but clearly it will be early March before the shrubs can oblige a surge of hummingbirds. In days gone by, the First People sought possession of stands of salmonberry for its luscious fruit. The Rufous covet the plant for its nectar, waging fierce battles over the finest flowers in their own statement of territoriality. When I began studying island wildflowers, I discovered several classic books that captured the essence of the early field biologists' interest with this connection between the first flowering plants and the arrival of the Rufous Hummingbird. There is one especially fine passage by Leslie L. Haskins in Wild Flowers of the Pacific Coast (1967) in which he wrote: "In late March the wild currant bursts into bloom, covering every bush with crimson panicles, and with it come a host of rufous hummingbirds, brilliant in glittering coppery mail, to buzz and twitter and chase each other noisily from bush to bush. These two brilliant friends are sure and inseparable in their springtime tryst, and together make one of our most colorful and animated pictures. A full-blooming shrub of this species shimmering in the sunlight through the dim, dark arches of a fir forest, has a glowing, ethereal quality, as though woven of soft-tinted gossamer, and floating lightly in the golden atmosphere." P.A. Taverner in Birds of Canada (1934) referred to the Rufous as a "gay Lothario" that followed the flower season up the mountain sides and in alpine meadows. Ralph Hoffman in Birds of the Pacific States (1927) wrote of the Rufous fighting over lemon and orange blossoms in the orchards of southern California as they passed through during spring migration, and called the birds "feathered atoms" dashing toward each other in a tempest of angry squeaks as they vied to refuel their high-strung systems before continuing up the coast. As they get farther north, the Rufous Hummingbirds seem to prize the red-flowering currant above the rest. So did Northwest explorer David Douglas. In 1826, he was enchanted by the plant, and took seeds back to England and introduced the showy Ribes to European gardens. Douglas was rewarded in fees that paid for his expedition. Thus, the lure of the currant continues. Moving toward March, the first Rufous migrants are likely nearing our region. This time last year, they had been sighted at several locations in Oregon including Astoria, Coos Bay, and Florence, at Gig Harbor and Maury Island, Washington and Nanaimo, British Columbia. These vanguard birds are often on the leading edge of the flower stream. A cold spell could stall them along the way, or unseasonably warm weather, like we had last week, could hasten the bloom and perhaps their arrival here. In years past, sightings of Rufous Hummingbirds have been reported at Anacortes on February 28, and on Guemes Island the first week of March. The male Rufous arrive first to secure nest sites, and the females are usually about two weeks behind. By April, courtship and nesting is underway. When the currant and salmonberry go to seed, orange honeysuckle becomes one of the hummingbird's favorite sources of nectar. Its striking trumpet-shaped flowers seem perfectly designed to receive Rufie's long sword.
So, even though the swans of winter are still grazing in San Juan Valley, it is not too early to have hummingbirds on our minds. I welcome your reports on red-flowering currant and Indian-plum, and the appearance of the first hummingbirds in your yard. It would be fun to do a follow-up, and to ascertain some of the islands' earliest arrivals. Some of our first Rufous sightings may be of birds stopping over here on their way to Canada, or as far north as Sitka and Juneau, Alaska. The blooming wildflowers show them the way, but I suspect a freshly filled hummingbird feeder might also be welcome to these extraordinary long-distance travelers that still have hundreds of miles to go before reaching home.
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